A carbon nanotube (CNT) can be described as a honeycomb lattice rolled into a cylinder. The carbon nanotube typically has a high aspect ratio and, therefore, possesses a high ratio of surface area to volume. Carbon nanotubes possess unique mechanical, thermal, and electrical properties. For example, carbon nanotubes can be highly conductive. Carbon nanotubes have also been shown to emit fluorescent light when excited by a laser beam of the appropriate wavelength and can emit incandescent light when current is allowed to pass through the nanotubes.
Carbon nanotubes have high mechanical strength by themselves. The interactions between carbon nanotubes produce non-chemical bond forces, such as Van der Waals forces, to maintain bundles of carbon nanotubes. To increase these forces, a close proximity between adjacent carbon nanotubes is desirable. One method for achieving this close proximity is the growth of dense groups of carbon nanotubes on a substrate.